This invention relates in general to pipe-laying equipment, and, in particular, to apparatus operable from opposite sides of a trench for continuously lifting and laying pipe into the trench.
More specifically, but without restriction to the particular use which is shown and described, this invention relates to an apparatus including self-propelled vehicles positionable on opposite sides of a trench and connected through an intermediate connection bridge for lifting and positioning pipe within the trench.
Various types of pipe-laying equipment have been utilized to lift and position pipe within a trench. Such equipment includes self-propelled counterweighted vehicles which utilize counterweight apparatus to balance the vehicle during operation of the pipe-laying equipment. Such systems are generally employed along one side of a trench and, therefore, necessitate that the pipe-laying vehicle be counterweighted to maintain vehicle stability during the pipe-laying operation. Another type of pipe-laying system utilizes a carriage running along abridge which extends across the trench. This latter type of pipe-laying system requires the use of control and driving means to position and stabilize the running carriage and requires a complicated and complex structure and controls for the equipment. It is, therefore, an object of this invention to improve pipe-laying equipment.
Another object of this invention is to simplify the structure and controls of pipe-laying equipment which is operable along both sides of a trench.
These and other objects are attained in accordance with the present invention wherein there is provided a pair of self-propelled vehicles joined by an intermediate bridge having a rigid lifting arm hinged at one end to the intermediate bridge and having a device for gripping and lifting the pipes carried by the free end of the rigid arm such that the rigid lifting arm may be controlled to engage a pipe and lift it over the trench and lower the pipe into the desired position.